Staring directly at Vivienne Westwood's vagina made me think of a number of things; mostly, however, it made me think about the difference between Nude and Naked, the nude – one assumes – being somehow formalised, and lacking in sex appeal. The vagina in question forms the centerpiece of Juergen Teller’s retrospective at the ICA, the exuberantly entitled ‘Woo!’

(Hard to imagine any other photographer using such a title; harder, still, to imagine one living up to it with the same dumb-clever panache.)

The great success of the nude, the art writer Frances Borzello argues, "has been to distance the unclothed body from any uncomfortably explicit taint of sexuality, eroticism or imperfection." This is, I guess, a good enough description of "nudeness" as a trope in art; the Westwood shots, a triptych, are technically pegged as "nudes," although there is a greater "nakedness" to them, as if the sixty-eight-year-old subject were being photographed as a kind of naughty private gesture, or a ribald joke. The designer's fiery pubis is front-and-centre: a confrontation (or "genital panic," if you like, to borrow the right-on phraseology of Valie Export) that dares the viewer to balk at her age. Her body, certainly, is not in the lissome shape of Lily Cole’s (whose implants, incidentally, I found fascinating in Teller’s shots – in one, where she lifts her arms, they’re almost Cronenbergian in their falseness) but there is a taboo sexiness to it; a gerontophile frisson. She looks like an ageing and gilded courtesan, all bloodless and gleaming and rare; Teller, with his camera, is the mirror for her practiced seduction.

Teller’s models, when bare, are generally nakeds rather than nudes – ebullient and human, and lacking in the kind of objectified nastiness peddled by, say, a Terry Richardson, or an Olivier Zahm; a different kind of agency. A sense of humour, perhaps, is Teller’s secret – his ace in the hole. There is a definite tendency towards the laugh-out-loud visual gag, from the legs of the pop star Victoria Beckham poking, absurdly, from a carrier bag, to the small, damp dog in the kitchen sink; the picture of a stuffed cat placed – with intent – next to Dame Westwood’s cheeky and bawdy crotch shot.

There is less literal nakedness being exhibited, too – an emotional nakedness, of a sort, emits a constant low-level hum of bathos, underscoring the general aesthetic of rubble and ruin and unburnished life. This, after all, is a style of photography that, though now familiar, was seminal in the 90s: it shoots for the kind of realism that can turn advertising to art. The pictures of the artist’s children, especially, are uniformly masterful, shot through with genuine feeling as warm as his usual colour palette (and oh, that palette – the autumn bronzes and pinkish salmons of summer; the cornflower blue of the corrugated iron which serves to offset Kate Moss in her wheelbarrow).

Ed, Teller’s son, makes a great subject in particular, his tiny face a simulacrum of his father’s, and beaming with infant joy and wonder; an image of his sullen daughter, Lola, is funny for different reasons – like every teenage girl, it seems, she is wearied by her madcap dad.